Extensible support for rock drills



June 5, 1951 'F. M. SLATER vEXTENSIBLE SUPPORT FOR ROCK DRILLS Ill Filed Oct. 8, 1947 HIS ATTORNEY.

Patented June 5, 1951 UNITED STATES PATENT OFFICE EXTENSIBLE SUPPORT FOR ROCK DRILLS Fred M. Slater, Phillipsburg, N. J., assignor to Ingersoll-Rand Company, New York, N. Y., a corporation of New Jersey Application October 8, 1947, Serial No. 778,668

(Ol. Z55-53) 1 Claim. 1

This invention relates to rock drilling mechanism, and more particularly to an extensible support for rock drills of the drifter type.

One object of the invention is to enable the support to be quickly extended for engagement with the surfaces supporting it.

Another object is to permit of the application of a powerful force for extending the support and to press its terminal portions into rm engagement with the surfaces supporting it.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawings accompanying this speciiication and in which similar reference numerals refer to similar parts,

Figure 1 is an elevation, partly broken away, of an extensible support constructed in accordance with the practice of the invention,

Figure 2 is a similar view of a detail, and

Figure 3 is a transverse view taken through Figure 1 on the line 3-3.

Referring more particularly to thev drawings, 28 designates, in general, the extensible support and 2| and 22 the surfaces supporting it, as for example the floor and the roof of a tunnel.

The support 2 comprises a tubular body 23 which extends at its lower end into a base 24 having calks 25 for engagement' with the surface 2|. The tubular body 23 is secured to the base 24, as by welding material 26, and in the free end of Vsaid body is a bearing surface 2l for a hollow rod 28 carrying a pointer 29 at its outer end for engagement with the surface 22.

The rod 28 is freely slidable on the bearing surface 21 so that it may be conveniently moved by hand and, in accordance with the practice of the invention, means are provided for locking the rod 28 securely in xed position with respect to the base 24 and to move it endwise for lengthening or shortening the support. To this end the support is provided with holding means shown as a pushout chuck 38 which comprises a series of jaws 3| the exterior surfaces 32 of which are contoured to conform with the curvature of the inner surface of the rod 28.

rIhe inner surfaces 33 of the chuck jaws. 3| are shaped for engagement with a coniform surface 34 on a plunger 35 extending axially of the tubular member 23 for pressing the jaws 3| against the rod 28. The jaws 3| are normally urged in the direction of the end of the larger diameter of the coniform portion 34, and thus into engagement with the rod, by a spring 36 that seats at one end against shoulders 3i' on the jaws 3| and at its other end against a ange 38 on a block 39 2 slidable upon a stem 4U at the upper end of the plunger 35. The free end of the stein 40 is threaded and a nut 4| thereon serves as an adjustable abutment for theblock 39 to vary the tension of the spring 36.

In the end of the block 39 confronting the jaws 3| is a coniform recess 42 to engage similarly shaped surfaces 43 of projections 44. on the jaws 3l for guiding the jaws 3| out of engagement with the rod 28 whenever the pressure of the plunger 35 is removed from the jaws. The inner surfaces 45 of the projections 44 are contoured for engagement with a cylindrical surface 46, between the coniform surface 34 and the stem 4, serving to maintain the jaws 3| in coaxial relationship with the rod 28 in order that all the jaws will move into and out of engagement with the rod in unison.

The means serving to release the chuck jaws from the rod 28 preferably consists of a sleeve 41 that encircles the plunger 35 below the jaws 3| so that when the rod 28 is drawn downwardly the jaws 3| will abut the end of the sleeve 4l and will remain stationary while the coniform surface 34 is drawn out of engagement with the jaws to release the pressure thereagainst. The sleeve 41 has an external ange 48 to support the rod 28 when the support 28 is fully contracted, and at the lower end of the sleeve 4l is a flange 49 that overlies the end of the tubular body 23 and seats upon a shoulder 5 in the base 2li for` maintaining the sleeve 41 in the correct assembled position.

In order to actuate the plunger 35 endlwise its lower end is provided with threads 5| for cooperation with the threads 52 of a nut 53 rotatable within the sleeve 41 and having a bevelled gear 54 at its lower end that seats upon an antifriction bearing 55 supported by the base 24. The gear 54 meshes with a pinion 56 of a shaft 5l rotatable in the base and having a crank 58 for manually rotating the nut 53 to impart endwise movement to the plunger 35.

An arm 59 is shown arranged on the tubular body 23 to serve as a support for the rock drill (not shown) and is secured to the body 23 by a clamp and bolts 8 In the operation of the device, whenever it is intended to extend the support 20 the nut 53 is rotated a partial revolution, by operation of the crank 58, to move the plunger 35 and the rod 28 downwardly until the chuck jaws 3| are brought into engagement with the end of the sl-eeve 4l.

` Continued movement of the plunger in the same coniform surface 34 against the chuck jaws and thereby release the rod 28. The rod may then be freely moved by hand to bring the pointer 29 into engagement with the surface 22. If the nut 53 is then rotated in the opposite direction the coniform surface 34 will first drive the chuck jaws outwardly into engagement with the rod 28 and the rod will thereafter move with the plunger to force the pointer 29 and the calks 25 into the supporting surfaces.

As will be apparent to those skilled in the art, by enabling the rod 28 to be released from the elements whereby the terminal portions of the support are driven against the surfaces 2l and 22 the support may be quickly extended and shortened, as required, and the pointer 29 may be brought into engagement with the surface 22 in considerably less time than would be possible if it could move only at the rate of movement of the plunger, as imparted thereto by the nut 53. At the same time the pointer 29 may be driven into the surface 22 with the same force that it would be were the plunger threadedly connecd to the rod 28.

I claim:

An extensible support for rock drills, comprising a tubular body, a base therefor, a rod freely slideable endwise of said body for varying the length of the support, chuck jaws for gripping the rod, a plunger having a tapered portion engag- Ying the jaws for pressing said jaws against the rod, a spring for normally holding the jaws in engagement with the rod, an abutment within the tubular body for moving the jaws out of engagement with the tubular body upon movement of the plunger in one direction, and a rotary member in the base in threaded engagement with the plunger to impart endwise movement to the plunger for forcing the jaws into engagement with and releasing them from the tubular body.

' FRED M. SLATER.

REFERENCES CITED i The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 595,465 Brennan Dec. 14, 1897 626,836 Larsen June 13, 1899 725,085 Jacob Apr. 14, 1903 776,881 -Ambrose Dec. 6, 1964 FOREIGN PATENTS Number Country Date 482,242 France Dec. 8, .1916 590,994 France Mar. 31, 1925 23,738 Great Britain Y A 1897 32,409 Austria Mar. 26, 1908 

